Nosocomial outbreak of the Middle East Respiratory Syndrome coronavirus: a phylogenetic, epidemiological, clinical and infection control analysis

Background: Middle East Respiratory Syndrome coronavirus (MERS-CoV) continues to cause intermittent community and nosocomial outbreaks. Obtaining data on specific source(s) and transmission dynamics of MERS-CoV during nosocomial outbreaks has been challenging. We performed a clinical, epidemiological and phylogenetic investigation of an outbreak of MERS-CoV at a University Hospital in Riyadh, Kingdom of Saudi Arabia. Methods: Clinical, epidemiological and infection control data were obtained from patients and Healthcare workers (HCWs). Full genome sequencing was conducted on nucleic acid extracted directly from MERS-CoV PCR-confirmed clinical samples and phylogenetic analysis performed. Phylogenetic analysis combined with published MERS-CoV genomes was performed. HCWs compliance with infection control practices was also assessed. Results: Of 235 persons investigated, there were 23 laboratory confirmed MERS cases, 10 were inpatients and 13 HCWs. Eight of 10 MERS inpatients died (80% mortality). There were no deaths among HCWs. The primary index case assumed from epidemiological investigation was not substantiated phylogenetically. 17/18 of MERS cases were linked both phylogenetically and epidemiologically. One asymptomatic HCW yielded a MERS-CoV genome not directly linked to any other case in the investigation. Five HCWs with mild symptoms yielded >75% full MERS-CoV genome sequences. HCW compliance with use of gowns was 62.1%, gloves 69.7%, and masks 57.6%. Conclusions: Several factors and sources, including a HCW MERS-CoV ‘carrier phenomenon’, occur during nosocomial MERS-CoV outbreaks. Phylogenetic analyses of MERS-CoV linked to clinical and epidemiological information is essential for outbreak investigation. The specific role of apparently healthy HCWs in causing nosocomial outbreaks requires further definition

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population